This slide shows a parapodium from a polychaete worm.This biramous appendage consists of a ventral division called the neuropodium and a dorsal division called the notopodium, each of which is supported by a stiff chitinous rod called an aciculum.  A dorsal cirrus and ventral cirrus (richly supplied with sensory receptors) project from the notopodium and the neuropodium respectively. Numerous dark staining setae that extend beyond the parapodium can also be seen on this slide.